Oil well heater



J. H. EADES OIL WELL HEATER Nov. 6, 1962 2 Sheets-Sheet 1 Filed Jan. 21,1960 JOHN HENRY EADES A TTORNE Y J. H. EADES OIL WELL HEATER Nov. 6,1962 2 Sheets-Sheet 2 Filed Jan. 21, 1960 lllllllllllm FIG. 5. ||||l|||lJOHN HENRY EADES FIG. 6.

A TTORNE Y United States Patent *Ofiiice 3,062,289 Patented Nov. 6, 19623,062,289 OIL WELL HEATER John Henry Eades, Dallas, Tex., assignor ofone-half to Charles E. Foote, Dallas, Tex. Filed Jan. 21, 1960, Ser. No.3,839 1 Claim. (Cl. 166-61) This invention relates to heaters for oilwells and has reference to improvements in apparatus wherein heatedfluids, for example steam or water, are circulated in a bore hole fortransferring heat to a producing earth formation.

The present invention is for use in both primary and secondary recoverywhere paraflin or asphalt accumulate in the producing zone around thebore hole. Reducnig the viscosity of oil promotes flow and tends toseparate entrained gas and water emulsions. Additionally, heat reducesthe viscosity of parafiin and asphalts in the oil and promotes flowwithin the formation.

Heretofore, oil well heaters have been used with some degree of successbut were inefiicient in their operation because considerable heat waslost in the annulus between the casing and the tubing. Another loss ofheat was by conduction in the tubing itself.

An object of the invention is to increase production in oil wells byreducing the viscosity of oil in an earth formation around a bore hole.

A particular object of the invention is to heat producing formations byconduction rather than radiation and thereby effect greater eflieiencyof the heater.

Another object of the invention is to provide means for at leastpartially insulating the heater from the well and well tubing.

Another object of the invention is to provide a well heater havingdirect contact means with the bore hole, yet which means may be readilyremoved when it becomes desirable or necessary to remove the heater fromthe well.

A further object of the invention is to provide means for reducing orpreventing sand from entering the well tubing, together with means forrepelling sand which may accumulate around the outer surface of theheater.

These and other objects will become apparent from the followingdescription and accompanying drawings, wherein:

FIGURE 1 is a broken elevation and sectional View of a preferred form ofthe invention.

FIGURE 2 is a transverse sectional view taken on line 2-2 of FIGURE 1.

FIGURE 3 is a transverse sectional view taken on line 3-3 of FIGURE 1.

FIGURE 4 is a broken vertical sectional view taken approximately on line4-4 of FIGURE 3 and additionally showing the present heater installed ina bore hole.

FIGURE 5 is a broken perspective view of an exemplary well head employedin connection with the invention.

FIGURE 6 is an elevation and broken sectional view of a modified form ofthe invention.

FIGURE 7 is a transverse sectional view taken on line 77 of FIGURE 6,and

FIGURE 8 is a transverse sectional view taken on line 88 of FIGURE 6.

The form of the invention shown in FIGURES 1 through 4 includes atubular insulator 10 of a suitable thermal setting synthetic resin, suchas Bakelite, overhanging upper and lower disk-like closures 11 and 12,and inner and outer vertical connecting bars 13 and 14. A heatingelement in the form of a coil 15 is positioned around the inner framebars 13 and the insulator 10, the ends of which coil have verticalextensions 16 and 17 which are connected with pipes 18 and 19 (shownonly in FIGURE 5) extending to the earths surface where they areconnected with means circulating hot water therethrough. The verticalextension 16 connected with the lower end of the coil 15 is hereindesignated as the supply lead, but circulation in either direction iseffective and within the scope of the invention.

The well tubing 20 has a lower perforated extension 21 within thetubular insulator 10, and which perforated extension is connected withthe well tubing by means of a collar 22 located in an opening in theupper closure 11. Similarly, the lower end of the perforated extension21 is connected with a fitting 23 in the lower closure 12, and whichfitting has a cap 24 in the lower end thereof.

The tubular insulator 10 has multiple horizontal slots 25 for admittingwell fluids, and there is a screen wire strainer 26 around the insulatorto prevent sand from passing through the referred to slots. It is to beunderstood that the slots 25 comprise the preferred construc tion butthat other configurations of openings may be employed. In the upperclosure 11 there is a fluid pressure supplypipe 27 which extends intothe insulator 10, and the upper end of which pipe has means connectingthe same with the earths surface and a supply of fluid pressure which isapplied when necessary for reasons hereinafter set forth.

Other details shown include a suitable bracket 28 atop the upper closure11 for engaging the extending portions of the supply lead 16, returnportion 17 of the coil 15 and the pressure supply pipe 27. The ends ofthe insulator 10 are received in grooves, not numbered, in opposingfaces of the closures 11 and 12 and the vertical bars 13 and 14 aresecured in their described positions by screws, not numbered.Preferably, the tubular insulator It) is asymmetrical with reference tothe axis of the coil 15 so as to accommodate the lead 16 and returnportion 17 so that the latter will not contact the well bore wheninstalling or removing the described construction.

As shown in FIGURE 4, the described heater is installed in open hole ofa producing formation 29 and gravel 30 is filled around the coil 15 andagainst the screen 26. Thus, heat from the coil 15 is transferred to theformation 29 through the gravel 30.

If sand migrates to and clogs the screen 26 fluid pressure is appliedthrough the pressure supply pipe 27 to force the sand back and open thescreen. When it becomes necessary or desirable to remove the heater fromthe well bore liquid pressure of considerable force is applied throughthe pressure supply pipe 27 forcing the gravel 30 up the well annulus,and while the gravel is suspended the heater is raised at least to adistance higher than the gravel when the latter is settled in the borehole.

While the form of the invention illustrated in FIG- URES 1 through 4 isintended primarily for operation with heated liquid, the form of theinvention illustrated in FIGURES 6 through 8 is intended for operationwith steam. The latter form of the invention includes the describedslots 25 therein, screen 26 therearound and perforated extension 21connected with the lower end of the well tubing 20. Instead of the upperand lower closures 11 and 12 there are upper and lower steam chambers 31and 32 which are secured in spaced relation by means of vertical rods 33connected therebetween. The heating elements are vertical tubes 34connected in communication between the upper and lower steam chambers 31and 32 and outwardly of the insulator 10 and screen 26. Beneath thelower steam chamber 32 there is a sump 35 which houses steam traps 36mounted in the bottom of said lower chamber. The steam supply line 37 isconnected in communication with the upper end of the upper steam chamber31, whereas the steam return line 38 extends from the interior of thesump 35 upwardly the insulator 10 and through the upper steam chamber31. As in the first described form of the invention, there is a pressuresupply pipe 27 in communication with the interior of the insulator 10for removing sand from the screen 26 and for loosening the gravel 30when removing the heater from the well. The closure at the lower end ofthe perforated extension 21 is a projecting boss 39 on the upper surfaceof the lower steam chamber 32. The operation of the last described formof the invention is substantially the same as described in connectionwith the first form of the invention.

The well head 40 illustrated in FIGURE 5 is exemplary and it is to beunderstood that various commercially available well heads may be used inconjunction with the present well heater. The well head 40 shownincludes a vertical nipple 41 and a laterally connected oil flow line42. The laterally extending fluid supply and return lines 18 and 19, andthe pressure supply line 27 have the same reference numerals as thosedescribed in the foregoing.

The invention is not limited to the constructions herein shown anddescribed, but may be made in various ways within the scope of theappended claims.

What is claimed is:

Apparatus for heating production formations in oil wells having a stringof tubing therein, said apparatus comprising a vertical perforated tubeconnected with the lower end of said tubing, a tubular insulator aroundsaid perforated tube, closures at the end of insulator and at the lowerend of said perforated tube, means admitting the flow of fluids throughthe cylindrical wall of said insulator, a hollow heating element meansaround said insulator, means circulating heated fluid through saidheating element means, and an applied permeable mass between and incontact with said heating element means and said production formation.

References Cited in the file of this patent UNITED STATES PATENTS2,276,401 Joslyn Mar. 17, 1942 2,349,536 Bancroft May 23, 1944 2,911,047Henderson Nov. 3, 1959

